Antenna Identification

SoonerAviator

Final Approach
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Broken Arrow, OK
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SoonerAviator
Found an antenna in our crawl space above the master bedroom. I don’t know a thing about antenna design, and there’s no apparent mfg data labels on them. They were mounted with the larger unit above the smaller one with a pair of wires connecting the leads together. Anyone know what they are designed for?

I assume TV VHF, but honestly am just guessing.

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I’m sure the HAM “people” will know, but I’m digging the flooring man! What is that?
 
I’m sure the HAM “people” will know, but I’m digging the flooring man! What is that?

Supposedly Mexican terrazzo tile original to the mid-60s house. There’s a ton of it in our living room/office. It’s definitely unique and is showing its age a bit, but that’s understandable for 50yr old tile.


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Looks like a typical combo VHF-UHF TV antenna from days gone by.

Kind of what I figured, but I wasn’t sure if UHF was included since most of the UHF antennas I researched seem to have more of a “loop” for the array than individual rods for the elements. The element length on the UHF antennas I viewed seemed to be pretty short as well, presumably to match the frequency wavelength.

Oddly enough, there was another outdoor antenna mounted up there as well, which had mfg data on it and was VHF/UHF/FM all mounted on one boom. It was a pretty nice unit, but I dunno why they chose to mount two outdoor antennas versus just using a splitter with one. I suppose they were already at the limit of the signal strength and the loss of a few dB through a splitter could have made it unusable. Always interesting to discover prior owners “improvements”.

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Well, the one on the left isn't fully deployed. Those elements that are pointing "up" should be more "down" than they are. Log periodic dipole array antenna, designed for some gain, but mostly wide bandwidth. The VHF television band covers two chunks of spectrum. 54 to 88 MHz (channels 2 through 6) and 174 to 216 MHz (channels 7 through 13). Looks like (without measuring) the elements that are folded are for channels 2 through 6 and the non-folded elements are for channels 7 through 13. Just a guess, but probably not too far off.

UHF television starts at 470 MHz (channel 14) and ends at 806 MHz (top of channel 69). Used to go higher as the channel numbers used to go beyond channel 80 (83?). That spectrum (806 MHz and up) has been given to other users (mobile phones, two way communications).

Interesting looking at the antenna on the right, it looks more like a Yagi-Uda array (AKA - Yagi). One driven element, one reflector and 3 directors. Typically designed for a narrow band of frequencies and some gain. I'd have to have a tape measure on the actual antenna to measure the element length (driven element) to see what frequency it was designed for.

The VHF/UHF/FM antenna was likely a log periodic dipole array with extra elements to work in the FM band (which starts at the top of TV channel 6 (88 MHz) and goes up to 108 MHz (bottom of aeronautical band)

I haven't used one of these antennas in decades. We've been on cable of one sort or another since late 1979. Oh, and yes, I'm guilty of being an amateur radio operator (Ham). Call sign is N6TPT.:D Also 42 years experience as an EMC engineer, and antennas are an essential tool of the trade.
 
One on the right may be home grown? It's been a million years, but way back in broadcast TV days, I mapped the transmitters in the DC area and aligned an element with each xmitter, to optimize reception. Other than the pictured one being all aligned together, it looked very much like it. Could it be it was mounted on a base that could be rotated?
 
Based on the spacing of the driven elements, the big one is a VHF Yagi and the smaller one is tuned for UHF.

Feeding them from a a single 300 Ohm twinlead would work great for dual band reception.

Yep, I'm a ham. K4IVE: https://www.qrz.com/db/K4IVE


Perfect.... Now we know where you live too.... I'm a Ham, but I'll never post my call sign...
 
I have a big ole Radio Shack VHF/UHF antenna sitting in the attic as well. It works perfectly fine for broadcast HDTV.
 
Well, the one on the left isn't fully deployed . . . The VHF/UHF/FM antenna was likely a log periodic dipole array with extra elements to work in the FM band (which starts at the top of TV channel 6 (88 MHz) and goes up to 108 MHz (bottom of aeronautical band)

Oh trust me, it was fully deployed in the attic, lol. I had to collapse the elements down in order to get it out since it probably measures 6-8' wide when fully deployed. The other antenna does resemble some of the log periodic arrays that pull up with a Google search.

Edit: the driven element length on the Yagi is 13.5” if that makes any difference, with the last element being a bit longer.
 
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One on the right may be home grown? It's been a million years, but way back in broadcast TV days, I mapped the transmitters in the DC area and aligned an element with each xmitter, to optimize reception. Other than the pictured one being all aligned together, it looked very much like it. Could it be it was mounted on a base that could be rotated?

No, this one was pretty shoddily mounted to a thin piece of wood strung between the floor and roof (only about 4' of vertical space). The array on the right was mounted above the array on the left, but they weren't really even secured to the wood, just loosely clamped and likely not ideally aligned. I live within 10 miles of most of the Tulsa-area TV transmitters, so I doubt it'd have to be perfect to get strong signal reception. Both of them appear to be of the same manufacturer (blue anodized booms), but I suppose it could have just been sourced from different parts and assembled that way.
 
I have a big ole Radio Shack VHF/UHF antenna sitting in the attic as well. It works perfectly fine for broadcast HDTV.

The funny thing is, I mounted one of the ClearStream 2V antennas on a j-pole up above a coat closet about a year ago to get better signal for the living room tv, not knowing that I had two VHF/UHF antenna arrays less than 15' away on the other side of the wall, lol. I haven't had any reason to go into this crawl space until I was looking at changing out some canned lights and went up to take a look.
 
Perfect.... Now we know where you live too.... I'm a Ham, but I'll never post my call sign...

Dude, all my personal data as well as government stuff nobody is supposed to have access to has been exposed in just about every data breach in the last 15 years. Every kid in China probably has my SSAN on their lunchbox...
 
Dude, all my personal data as well as government stuff nobody is supposed to have access to has been exposed in just about every data breach in the last 15 years. Every kid in China probably has my SSAN on their lunchbox...

Naw.... They have been using it for SSA, WIC, SNAP, Obamacare, voting, .... oh yea, how are you liking that new truck you, er, they bought?
 
Fed with one twinlead, I'd agree they are just V/UHF TV antennas. With a different feed arrangement, I'd recall that an awful lot of old TV antennas got used as parts for ham VHF and UHF Yagis.
 
Oh trust me, it was fully deployed in the attic, lol. I had to collapse the elements down in order to get it out since it probably measures 6-8' wide when fully deployed. The other antenna does resemble some of the log periodic arrays that pull up with a Google search.

Edit: the driven element length on the Yagi is 13.5” if that makes any difference, with the last element being a bit longer.

And the three elements in front of the driven element should be a touch shorter.

13.5 inches for 1/2 lamba. Wavelength is 27 inches, .69 meters. Tuned frequency is, therefore, 437.45 MHz. Near the middle of the 70 cm ham band. I'll bet I have one out in the garage that isn't significantly different. I wonder what that was doing in the attic?
 
I have a dual band, 2m and 70cm tape measure Yagi in my attic. It is pointed at the repeater just South of my house.
 

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And the three elements in front of the driven element should be a touch shorter.

13.5 inches for 1/2 lamba. Wavelength is 27 inches, .69 meters. Tuned frequency is, therefore, 437.45 MHz. Near the middle of the 70 cm ham band. I'll bet I have one out in the garage that isn't significantly different. I wonder what that was doing in the attic?

I will clarify that the measurement of the element was just supposed to be for one side and not all the way across, correct? The twin lead between the two arrays was very light-gauge wire (like 20-22ga). However, the twin lead coming from the subfloor of the attic TO the antenna was some stout stuff (probably close to 12-14ga wire). It was also in a heavy protective sheath that initially had my attention because it was closer to looking like electrical romex. I could not discern where the end of said cable went once it when below the subfloor, and I've never seen any wire/outlet that it would go to on the interior of the house.
 
It's obvious. Your house was built by a Russian spy....


Funny. Installing and servicing outdoor TV antennas was once an entire industry..
 
It's obvious. Your house was built by a Russian spy....


Funny. Installing and servicing outdoor TV antennas was once an entire industry..

Go to my parents house and you’d think my father is a spy. 110’ Tower will multiple VHF Yagis, several inverted V HF antennas, and a full fledge weather station. Plus another “upside down umbrella” HF antenna on top of the chimney. Also a few microwave antennas aimed at various microwave sites in the local area.

Then he has several sat dishes aimed at various FTA satellites.

He really likes his HAM hobby!
 
No need for all caps in "ham"; it's not an acronym.
 
And the three elements in front of the driven element should be a touch shorter.

13.5 inches for 1/2 lamba. Wavelength is 27 inches, .69 meters. Tuned frequency is, therefore, 437.45 MHz. Near the middle of the 70 cm ham band. I'll bet I have one out in the garage that isn't significantly different. I wonder what that was doing in the attic?

I will clarify that the measurement of the element was just supposed to be for one side and not all the way across, correct? The twin lead between the two arrays was very light-gauge wire (like 20-22ga). However, the twin lead coming from the subfloor of the attic TO the antenna was some stout stuff (probably close to 12-14ga wire). It was also in a heavy protective sheath that initially had my attention because it was closer to looking like electrical romex. I could not discern where the end of said cable went once it when below the subfloor, and I've never seen any wire/outlet that it would go to on the interior of the house.

OK, that cuts the frequency in half. Now we're talking 218 and change MHz, bottom of the VHF High band for TV. My guess for the twin lead is that it is all 300 Ohm stuff. Typical for TV.

No need for all caps in "ham"; it's not an acronym.

Yup.
 
All this talk about dipoles and such firmly reinforces the fact I am totally clueless about radio waves.
 
All this talk about dipoles and such firmly reinforces the fact I am totally clueless about radio waves.

Yup, that's why I punted on it, lol. I had done some cursory research on typical antenna designs, but couldn't get far enough to get a quick answer on application since it involved mathematical equations I was unfamiliar with. I've jury-rigged a few antennas out of non-insulated wire to pick up an FM/low-VHF signal before, but it certainly wasn't designed to specifically capture any particular frequency.
 
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